Oroville Dam emergency

[Max Rockatansky]

MOD NOTE: This thread originated in the Pacific Southwest board. It was merged from tangent conversation in the Historic "drive through" Sequoia knocked down in storm thread and a separate "Oroville Dam possible failure" thread that derived from that. –Roadfro


The Sacramento Bee had a pretty good article on the spillway eroding at the Oroville Dam:

http://www.sacbee.com/news/state/california/water-and-drought/article131743014.html

[Max Rockatansky]

Pretty much everywhere in the state the rivers have been like that, I'm to understand it is even worse up north.  But then again they seem to be more flood prone, hence the conversation in the CA 169 thread.  That erosion though on the Oroville Dam spillway ain't good though, that isn't something that will be a quick fix.  It would be interesting to see if things stay like this over the next couple weeks if that emergency spillway will get opened, that would be pretty wild to see water running down the hillside.

[Max Rockatansky]

Guess they had to open the emergency spillway after all at Oroville:

https://www.yahoo.com/news/water-flowing-over-emergency-spillway-tallest-us-dam-185525996.html

[Rothman]

Weather Channel's reporting the spillway failure is going to cost $100m to fix when all's said and done.

[Max Rockatansky]

Weather Channel's reporting the spillway failure is going to cost $100m to fix when all's said and done.

I guess they expecting the crater to be ground down to bed rock by the water before everything is all said and done.  I might make it up that way later this month, I figure it would be pretty cool to get some photos of the damaged spillway if I can.

[kkt]

The emergency spillway is in use but there is significant risk of spillway failure.  Oroville and surrounding towns and low-lying areas as far away as some neighborhoods of Sacramento are being evacuated.
More in the Murky News:
http://www.mercurynews.com/2017/02/12/oroville-residents-told-to-evacuate-spillway-failure-imminent/

[kkt]

I made a separate topic for Oroville Dam, since it's now under evacuation as there is significant risk of complete failure:
https://www.aaroads.com/forum/index.php?topic=19684.0\

[jeffandnicole]

Weather Channel's reporting the spillway failure is going to cost $100m to fix when all's said and done.

No doubt it'll cost a lot of money, but this is more irresponsible talk from the Weather Channel.   What a convenient round number they throw out there.

How are they supposed to have a clue what it'll cost before the damage is inspected by engineers, and a design drawn up that may be more involved than what's there now?

[Max Rockatansky]

That's all sorts of bad.  Basically this whole thing has gotten worse everyday this week.  Suffice to say that it isn't just highways at risk but pretty much all of Oroville at this point.  I seriously hope anyone isn't stupid enough to stay until this gets under control.  The forecast looks REALLY bad for next week too.

[kkt]

News reports are that the water level is now below the emergency spillway so the chance of immediate failure is much lower.  But they're wanting to keep residents evacuated until the damage to both the emergency spillway and the regular spillway can be evaluated.

[Max Rockatansky]

Yeah sounds like if this can get things under control they might just have to reduce the capacity of the reservoir somehow like with Lake Isabella...at least until the main spillway gets fixed.  Basically this has gone straight to hell in the course of a single week, kind of amazing to consider that the emergency spillway has never been in use until now. 

[kalvado]

Looks like missed  strategy helped (or didn't help) as well: lakes were very low, and had plenty of flood control capacity - but water accumulation was prioritized. And inflow for 2/8-2/11 happened to be 2-3x more than release. And there was little capacity left....

[sparker]

There are several "forebays" downstream adjacent to the Feather River itself; they should have been utilized to relieve the main dam.  Also, the emergency spillway -- which is just a slightly lowered portion of the dam structure off to the side of the main spillway -- should have been fortified with concrete (or even gunite!) when it was being built instead of remaining just a ledge of packed earth, like the basic main dam structure.  If the emergency subsides, the reservoir level will likely have to be lowered to make any repairs or modifications, wasting water that could have been part of the ongoing drought relief.  IMO, not very thorough planning on the part of everyone involved.

[Max Rockatansky]

There are several "forebays" downstream adjacent to the Feather River itself; they should have been utilized to relieve the main dam.  Also, the emergency spillway -- which is just a slightly lowered portion of the dam structure off to the side of the main spillway -- should have been fortified with concrete (or even gunite!) when it was being built instead of remaining just a ledge of packed earth, like the basic main dam structure.  If the emergency subsides, the reservoir level will likely have to be lowered to make any repairs or modifications, wasting water that could have been part of the ongoing drought relief.  IMO, not very thorough planning on the part of everyone involved.

Apparently there was some sort of study back in 2005 that showed that the emergency spillway needed to be reinforced because it would likely erode:

https://www.yahoo.com/news/nearly-200-000-remain-under-085347693.html

[myosh_tino]

I made a separate topic for Oroville Dam, since it's now under evacuation as there is significant risk of complete failure:
https://www.aaroads.com/forum/index.php?topic=19684.0\

Just to clarify, the Oroville Dam itself is not in any danger of failing.  It's the emergency spillway that's located to the left of the dam on the other side of the hill that has officials worried.

NOTE: Local experts are saying that if the emergency spillway collapses, it would be considered a dam failure.

[Buck87]

I guess it would be a dam shame if that dam spillway collapsed

[Desert Man]

Oroville Dam in Northern CA, the US' tallest dam, an earthfill embankment dam at 770 feet, is damaged and the dam's water has been released, thus the risk of flooding down stream in the Oroville area is high. The reservoir received recent heavy rains after 7 previous years of drought, and the dam built 48 years ago has failing infrastructure. The towns of Biggs and Gridley in lower ground are going to be flooded, as the Feather River is currently at elevation 96 feet (above flood stage)...about to enter orchards, groves and fields east of these towns. 188,000-200,000 people are under evacuation orders, which means the cities of Yuba City-Marysville will be impacted by river flooding. I'm gonna keep you all posted while I watch livestream news coverage from Sacramento valley's TV stations.

[Max Rockatansky]

We got another one of these actually going in Pacific Southwest.  Last I heard yesterday was that they were trying to get the level of the lake down by 50 feet and possibly patch the main spillway with rocks.  Not that any of this is good but its pretty bad that literally a small fraction of the design capacity for the emergency spillway started to cause it to erode....especially when it was pointed out as a potential design flaw back in 2005.  At minimum a 30 emergency spillway caving in is a lot better scenario than the full 700 something height of the dam, either way there will be a crap ton of damage.

[myosh_tino]

Local experts are saying that if the emergency spillway collapses, it would be considered a dam failure.

Oh geez, what have I started!

Cool it with the dam jokes guys or else you'll raise the ire of the mods who don't find them that dam funny. 

[Max Rockatansky]

Local experts are saying that if the emergency spillway collapses, it would be considered a dam failure.

Oh geez, what have I started!

Cool it with the dam jokes guys or else you'll raise the ire of the mods who don't find them that dam funny. 

It does make the "build extra water storage now" signs in the Central Valley somewhat "dam ironic" all things considered.  Seriously hopefully I hope nothing happens with Oroville but the puns are tending write themselves.  Really there was at minimum a lot of over confidence when if not outright arrogance in the design of the dam when the main spillway started to crater, especially considering there was prior calls to upgrade the emergency spillway a decade ago.  I'm sure there is still someone out there claiming the drought isn't over, news articles to that effect were still coming out to the start of the month. 

[kkt]

If they have to let most of the water out of the reservoir before the summer growing season in order to repair the dam, the drought may be over but the water crisis will continue...

[Max Rockatansky]

If they have to let most of the water out of the reservoir before the summer growing season in order to repair the dam, the drought may be over but the water crisis will continue...

Yes but it is like nobody gets that the Central Valley and most of California is a desert or semi-arid.  All that water comes from snow pack and rain water in the mountains, there will never be consistent conditions without drought.  The problem is only made worse by the fact that there is almost 40 million people here now.  You have so many people acting like there is some great untapped River or water resource in the mountains when they are pretty much impounded already.  And just because you create another reservoir that doesn't mean there will be rain run-off and snow pack to fill it up. 

And really this isn't just a California thing.  The Colorado River watershed basically has all he same problems I just described in the desert states.

[kkt]

In California's case, it's not so much the additional people as the water-intensive crops being grown there, and lawns and golf courses.

[coatimundi]

In California's case, it's not so much the additional people as the water-intensive crops being grown there, and lawns and golf courses.

The majority of the golf courses in California now use reclaimed water, and much of the landscaping that's maintained by government agencies (including Caltrans) uses reclaimed and recycled water.
The funny thing with ag usage is that you hear a lot of bitching and moaning, but I personally believe that it's more they're complaining so loudly not because the situation is dire, but because they don't want anyone cutting into their supply. That was threatened a couple of years ago, and that's when the ag groups got really vocal and we started seeing these "dams not trains" signs everywhere. The fact is that, here in the Salinas Valley, where we don't have snowmelt, you self-report "estimates" on your groundwater usage. That seems ridiculous in light of a drought, but trying to move them onto the more standard, monitored usage model has been met with so much resistance over the years that the water district mostly gave up on the idea.

[kkt]

There's pretty good coverage of the Oroville Dam situation in the Sacramento Bee, see this story from today:
http://www.sacbee.com/news/state/california/water-and-drought/article132583524.html

Oroville update: Butte, Yuba and Sutter counties reduce evacuation order to warning